Vertcoin P2Pool FAQ

Since P2Pool is a great way to keep the network decentralised, and Vertcoin is a leader in the crypto world at promoting P2Pool mining, it seems to me that we need to make it easy for miners who are considering using P2Pool to understand the differences instead of being scared off by them.

This doesn’t cover any miner-software specific issues (such as vertminer configs or whatever), but rather just general P2Pool stuff.

General Questions

What is P2Pool? Why should I mine on it?

As the Bitcoin P2Pool article describes it, “P2Pool is a decentralized mining pool that works by creating a peer-to-peer network of miner nodes”. The most important aspect of P2Pool is that it is highly decentralised, operating through peer-to-peer communication between many, many nodes, as opposed to placing pooled mining power into the hands of traditional mining pool operators, thus greatly reducing the risk of 51% attacks on the network. P2Pool earnings are also paid directly to miners’ wallets, eliminating the need to trust pool operators to hold your coins, as well as avoiding paying transaction fees on payouts. Furthermore, while P2Pool nodes can have fees just like traditional pools, fees are generally lower, and it’s possible (and relatively simple) to operate your own, private P2Pool node, which confers many benefits, not least of all being 0% fees and zero downtime so long as your machine is connected to the network.

How do I mine on P2Pool?

The easiest way to connect to the P2Pool network is to connect to a public node. Vertcoin currently has three P2Pool networks, and public nodes for the three are listed on http://coin.cubeconnex.com/poollist/. For best results, miners will want to connect to a node with low latency, or even better, run their own nodes. For those so inclined, instructions for setting up a P2Pool node for Vertcoin are available on https://github.com/donSchoe/p2pool-n for both Windows and Linux. Once you’ve decided on a node, you can just connect to it using your wallet address as your username and anything (most people use x) as your password. Smaller miners may have a better experience using the second or third P2Pool networks due to the high share difficulty of the first network, but more on that later.

So I started mining on a P2Pool node… Why am I submitting a billion shares per minute/barely any shares at all?

P2Pool can be a little wonky with deciding what difficulty of work to pass to your workers, sometimes giving you work that’s way too easy, sometimes work that’s waaay too hard. This can be resolved by setting a manual difficulty for your miner, which is done by adding, “+“, to the end of your Vertcoin address. The most common suggestion I’ve seen for mining difficulty is * 0.00000116, though this can be modified to your preference (whatever gets you the least rejects). So, for example, running on a card that hashes at 150kH/s, your payout address might look something like: VdtekY6D8mC8q7wt9TMQCjqeeQkWMteyrc+0.000174.

I want to connect multiple mining cards to P2Pool. Should I use different payout addresses?

Probably not. It’s possible to connect multiple devices (with different difficulty settings) to the same address on P2Pool. Doing this will combine your payouts, which helps to reduce small, dust payouts to some degree. For example, you could have one card using the address Vdt…yrc+0.000174, and another using Vdt…yrc+0.0001972, and P2Pool will distribute work of the correct difficulty for both cards.

Is there a way to view individual worker stats?

Not really, though there is a workaround if you run a private node that lets you see the hash/stalerates of different devices in a bit of a roundabout way. If you set node fees to 100%, all shares mined at the node will be credited to whatever the node address is, which lets you set anything as your worker name for each device. In this way, all devices can be displayed separately, while still all crediting a single address with shares.

I’m mining away and getting lots of accepts, so why am I showing as having zero shares?

This is where P2Pool is most often misunderstood, so let me elaborate. A very important aspect of the P2Pool network is the sharechain, which operates similarly to (and in parallel with) the blockchain for the Vertcoin network, except that it rewards miners with P2Pool shares rather than with Vertcoin block rewards. Shares are generated in the sharechain like blocks are generated in the blockchain, except instead of targetting a 2.5 minute block time, it targets a 15 second share time. Essentially, everyone on P2Pool is solo-mining on the sharechain, and everyone who has found, “blocks”, (shares) on the sharechain within a certain period are entitled to a piece of the payout when blocks are found on the Vertcoin blockchain by the P2Pool network.

Why do my payouts look so bad after mining for a few hours?

P2Pool operates on an extended pay-per-last-N-shares (PPLNS) model. The more valid shares a miner has proportionate to others on the network, the larger payouts will be when blocks are found. Shares on P2Pool remain valid for a very long time compared to most traditional pools, lasting for the expected time required for the P2Pool network to find 12 blocks, or for 24 hours, depending on which is shorter. Because of this system, P2Pool payouts, “ramp up”, as you collect shares, until they stabilise as your shares start to expire. This should not be confused with lost profits as you build up your shares, as these, “losses”, will be accounted for if/when you stop mining, as your valid shares will continue paying out even after you stop hashing on the network.

How do fees on P2Pool work?

P2Pool fees, like most things on the P2Pool network, are tied to the sharechain. Rather than taking a flat fee off your earnings, P2Pool fees essentially give a percentage of your shares to the node. Basically, if a node has 1% fees, 1% of the work your miner receives will be flagged as belonging to the node. If this flagged work results in a share solution, the node will receive the share instead of you. As a result, P2Pool fees are less consistent than fees for traditional pools; you might mine on a node for weeks without paying any fees, or you might lose several shares in a row to fees.

I’m thinking about switching nodes on P2Pool. Will I lose my shares?

No! Shares on P2Pool are tied to your address; not to any node in particular. You may freely switch nodes without compromising your payouts. Since fees are also measured in shares, there will be no, “lingering payments”, made to nodes you previously found shares on or anything like that.

Troubleshooting

I’m getting high reject rates on my miner… is something wrong?

Maybe. P2Pool will naturally have higher rejects due to the fast, “block”, times of the sharechain, so it’s not ununsual to have higher rejects than you would on a conventional pool. If your rejects are similar to those shown on other nodes on the network (which you can check on each node’s page), there shouldn’t be a problem. Regardless, there are a few things you can do to reduce rejects (also applies to orphaned shares). Setting a manual difficulty on your miner may help, as the short block times of the sharechain can result in stales if your work takes too long to complete. On the network side, connecting to a node with lower ping will help greatly with stale rates. Making sure your internet connection isn’t being clogged up with other traffic may help as well. Finally, the best way to reduce stales resulting from network issues is to set up your own node, as this will naturally have the lowest (zero) ping to you.

I’ve been mining for X amount of time without getting paid/stopped getting paid. What’s up?

Either the P2Pool network hasn’t found a block, or you don’t have any valid shares―try checking the node stats where you’re mining and see what it says for your address. The latter problem can occur frequently for low hashrate miners on larger P2Pool networks due to the way the sharechain works (share difficulty increases with the P2Pool network size). The Vertcoin community has stepped up and addressed this issue to a degree by creating a second P2Pool network, which is recommended for smaller miners as the lower share difficulty results in less payout variance.

When I try to send coins mined from P2Pool, why do I have to pay transaction fees?

This is not a P2Pool specific issue, but can occur when coin inputs in your wallet are too new or too small to reach, “medium”, priority. Since P2Pool tends to pay out in small pieces, this can potentially result in fees when trying to spend your coin (though bear in mind that you paid no fees to receive your coin). However, it is possible to avoid these fees if you can combine your inputs to average out to medium priority. To do this, you’ll need to enable manual coin inputs in the Vertcoin wallet (Settings > Options > Display > coin control features). Once this has been done, the send tab will allow you to select manual inputs for sending coin. If you select a larger chunk of coin (say, 10VTC) at medium priority, you can also select a bunch of dust payments and have it average out to medium priority (no fees). If you then send this combined input to yourself, it’ll eventually mature back to medium priority, giving you more coins which can be sent with zero fees!

Other Questions

What are all these stats on the P2Pool node?

Local rate: The combined hashrate of all miners on a node. The DOA percentage reflects the rate stale (invalid) work is submitted to the node.

Global pool rate: The combined hashrate of the entire P2Pool network. The larger this is, the faster the network will find blocks, but the higher P2Pool share difficulty will be in return. The DOA rate here reflects the average stale P2Pool sharerate for the network, which is different from the DOA measurement in local rate.

Shares (orphan/DOA): P2Pool shares found by the node, the number outside the brackets representing the total shares found, including shares which are orphaned or DOA. Orphaned shares are found shares which are not extended by the rest of the network and therefore invalidated, and can be reduced by maintaining lower latency in communicating with the P2Pool network. It’s normal to have a certain orphan rate on P2Pool, with the average dictated by the global pool rate DOA percentage. DOA shares are shares which are already invalid by the time the miner submits them to a node, which is often the result of improper configuration (such as setting an invalid payout address).

Share difficulty: The difficulty target for finding P2Pool shares on the sharechain. This is measured using the same method as difficulty for the Vertcoin network, but should be much, much lower. Share difficulty becomes higher as the P2Pool network hashrate increases, and share difficulty which is too high can result in high variance for smaller miners.

Expected time to share (node/miner): The average time it should take to find a P2Pool share on the sharechain. Unless you are operating your own private node, you don’t really need to be concerned with the node sharerate, as you only get paid out for your shares anyhow.

Expected time to block: The average time it should take for the P2Pool network to find a Vertcoin block. When a block is found, all miners on P2Pool with valid P2Pool shares will receive a payout.

Node uptime: How long the node has been online. You probably want to mine on a node which isn’t going down all the time, right?

Predicted payout: Approximately the amount you will receive if a block is found by the P2Pool network right now. Note that this number may not completely accurately reflect your payout.

Other things should be more-or-less self-explanatory. If they’re not, let me know and I’ll add them!

Will I make more on P2Pool than on other pools?

No. Err, yes. Maybe? All things operating properly and assuming zero fees, there should be no difference in long-term profitability between mining on P2Pool, on a traditional pool, or even mining solo. However, not everything works optimally, and there are things which can effect your profitability on this-that-or-the-other. On P2Pool specifically, beyond fees, if you can keep your rejects/stale shares below the network average, your higher efficiency will actually confer increased profitability over others on the network. Conversely, high rejects/stales will result in comparatively lower profitability.

Why are there three* P2Pool networks?

The second P2Pool network was created to reduce variance for smaller miners. Going back to the sharechain, as the P2Pool network hashrate increases, the share difficulty also increases to keep consistent 10/15 second share times. At some point, smaller miners may no longer be able to consistently maintain valid shares, resulting in payout droughts (increased variance) between found shares. By operating a smaller, second P2Pool network, the hope is that a balance can be found for smaller miners where both shares and blocks can be found regularly enough to make the variance more bearable.

Now that the second network has grown quite large, a third network has been created, and this can continue on indefinitely, so hopefully there will always remain a place for smaller miners on P2Pool.

Hopefully this helps clarify many of the issues people have been having with P2Pool. This writeup covers the common questions I can remember seeing recently, though I’m sure there are others which I’ve missed. For further reading, you can check out the Bitcoin P2Pool wiki at https://en.bitcoin.it/wiki/P2Pool, which explains many of P2Pool’s mechanisms in a bit more depth―just ignore some of the timings for share generation and whatnot, as they’re different on Vertcoin’s P2Pool system. Also, the, “joining the pool”, section assumes you are setting up your own node, so none of the setup it lists is relevant if you’re just connecting to a public node.

source: http://www.reddit.com/r/vertcoin/comments/22hved/vertcoin_p2pool_faq/

Vertcoin P2Pool FAQ